When you add a customer or business customer, you can assign a payment method to the company. Future invoices for sales orders made by this customer will default to this payment method. If you do not assign a payment method to the customer, the default payment method set up in your general settings will be used.
To assign a payment method to a customer-first go to the Relationships page and select the customer you want to assign a payment method to.
Click to edit the customer information.
You will see a dropdown box called Default Payment Method. Click to view and select your payment method options.
Click on 'Save Changes'.
When you create a new sales order for this customer, this default payment method will be applied automatically.